Hello DIYers, architects, and everyone in between! Do you need to soundproof a wall? Whether you have an existing wall or are planning a new construction, Green Glue is a cost-effective solution that is so easy-to-apply, you can’t really mess it up. That reliability is why it’s such a popular choice for improving sound isolation and reducing airborne noise. While we often recommend Green Glue, there are plenty of other options out there so we’ll also jump into some Green Glue alternatives later in the article.
What Is Green Glue?
Green Glue is a non-toxic, high performance damping compound designed for use between building materials (often drywall). It improves STC ratings in a wide variety of construction configurations. (Sound Transmission Class, or STC rating, is a number value assigned to how much airborne sound a soundproof material or partition is able to stop.) It is used between layers of building materials, typically drywall, but also plywood and cement board. It comes in a 28oz tube that can cover 16 square feet or a 5 gallon pail you use to fill a special applicator. 2 tubes should be used per 4’ x 8’ sheet of drywall (32 sq ft). 3 tubes will improve performance, but you should not use more. There is no odor and it works right away, although performance continues to improve over the course of the 30 day cure period.
Green Glue is one of our “go to” products for soundproofing a room. Use it between layers of ⅝” drywall to a soundproof wall or a soundproof ceiling for airborne noise. It can also be used to decouple plywood for soundproofing between floors as part of a floor-ceiling assembly. Green Glue performs well as long as the two sheet layers are flat and rigid. It cannot be used between one or two soft layers or used as wall insulation or for exterior applications. We especially love this product for existing walls because by adding Green Glue and a new layer of ⅝” drywall, you can increase your STC rating into the low 50s without ripping out the current wall.
Green Glue Alternatives
For modifying existing walls, Green Glue is the best option. However, there are two Green Glue alternatives we recommend regularly. First is our Luxury Liner mass loaded vinyl. Mass loaded vinyl is an acoustical barrier that is excellent for blocking noise transfer while taking up minimal space. MLV is safer than lead and is denser than drywall. It is a high density, limp material that has been used for decades as an effective sound barrier. The best application of MLV is directly to the studs with 5/8” drywall on top. The entire perimeter and around any penetrations should be sealed with acoustical sealant.
The second Green Glue alternative is a sound isolation clip. We screw RSIC-1 clips to the studs, snap in 25 gauge hat channel, and then screw 5/8” drywall into that channel to decouple the wall and create a better sound barrier. RSIC clips are our preferred sound isolation clip because they are used in far and away the most UL rated assemblies and have official soundproofing tests to go along with just about any construction. They also offer a huge variety of types of clips for any unusual situations (most rooms just need the RSIC-1). RSIC clips stop both impact and airborne sound transmission through wall and ceiling assemblies. If you need top-end sound isolation, RSIC clips are the best possible solution and what we’d recommend over Green Glue, unless you need top TOP-end soundproofing, where we’d recommend you use the RSIC Clips and Green Glue together. For soundproofing a home or a commercial space, these are a great option. As with mass loaded vinyl, always seal gaps around the perimeter and any penetrations with acoustical sealant.
Green Glue vs Mass Loaded Vinyl
For construction projects, we often recommend MLV since it’s often what the construction company is looking for. However, Green Glue works great as well! It all depends on what you are comfortable installing. For an existing room, however Green Glue is definitely the preferred option because you can improve soundproofing without removing drywall. Just keep in mind that both Green Glue and MLV and ineffective when blocking structural noise like footsteps. RSIC clips are required if you have impact noise, like footsteps through a ceiling.
You can also use Green Glue and MLV together (MLV + ⅝” drywall + Green Glue + ⅝” drywall) if you have high STC requirements. Combining the two will give better performance, just like we referenced earlier with combining RSIC clips and Green Glue. Whatever your preferred method, you should use use acoustical sealant to seal any seams or gaps.
Acoustic Material (Foam) Is Not An Alternative
A Green Glue alternative we do not recommend using is any kind of foam on the outside of the wall. A common misconception is that there’s “soundproof” foam that can stop sound through a wall. Unfortunately, no acoustic material will prevent sound from traveling through a wall. Acoustic materials (like foam) are not dense and not meant to block sound.